The effect of pasture-based dam-rearing on attention bias after disbudding in dairy calves

Context Keeping cows and calves together promotes natural behaviours, improving calf growth and welfare. In other species, the dam’s presence reduces stress and improves offspring emotional affect when challenged. The impact of dam-rearing on calves’ ability to cope with painful procedures such as disbudding has not yet been investigated. Aim This study explored whether pasture-based dam-rearing influenced dairy calf behavioural responses indicative of affective state in an attention bias test (ABT) following disbudding. Methods Ten calves (Friesian, Friesian × Jersey) were separated from their dam at birth and group-reared indoors (commercial calves). Twelve calves remained with their dam at pasture (dam-reared calves). The calves underwent hot-iron disbudding at 6 weeks of age under sedation, local anaesthesia, and analgesic. The ABT was conducted 6 h post-disbudding, through exposing calves to a perceived threat for 10 s (i.e. a dog), and measuring their behavioural responses in the 3-min after threat removal. The effects of rearing treatment following disbudding were analysed using linear mixed models and Poisson regressions. Key results Commercial calves had more eating events in the 3-min following the dog’s removal (1.8 ± 1.99 vs 0.2 ± 0.60 eating events, P < 0.05), but there were no differences in attention or vigilance behaviour. Conclusions Under the conditions of this study, dam-rearing did not alter behavioural responses indicative of anxiety in an ABT. More research is recommended to fully elucidate whether affective experiences of calves are altered during painful husbandry procedures as a result of dam rearing versus commercial rearing systems. Implications The method of rearing did not affect negative affective states (i.e. anxiety) in a post-disbudding ABT. The stress from isolation, pain, or transportation may have influenced the results. Future methods should test calf affect without removing them from their treatment environment to better understand emotional experiences in dam-rearing systems.